﻿<p>The building storey has an elevation and typically represents a (nearly) horizontal aggregation of spaces that are vertically bound.</p>
<p>A storey is (if specified) associated to a building. A storey may span over several connected storeys. Therefore storey complex provides for a collection of storeys included in a building. A storey can also be decomposed in (horizontical) parts, where each part defines a partial storey. This is defined by the composition type attribute of the supertype <em>IfcSpatialStructureElements</em> which is interpreted as follow:</p>
<ul>
 <li><b>COMPLEX</b>: building storey complex</li>
 <li><b>ELEMENT</b>: building storey</li>
 <li><b>PARTIAL</b>: partial building storey</li>
</ul>
<blockquote class="example">
EXAMPLE&nbsp; In split level houses, a storey is split into two or more partial storeys, each with a different elevation. It can be handled by defining a storey, which includes two or more partial storeys with the individual elevations.</blockquote>

<p>The <em>IfcBuildingStorey</em> is used to build the spatial
structure of a building (that serves as the primary project
breakdown and is required to be hierarchical). The spatial
structure elements are linked together by using the objectified
relationship <em>IfcRelAggregates</em>.</p>


<p>Figure 3 shows the <em>IfcBuildingStorey</em> as part of the
s patial structure. It also serves as the spatial container for 
building and other elements.</p>

<blockquote class="note">NOTE&nbsp; Detailed requirements on mandatory element
containment and placement structure relationships are given in
view definitions and implementer agreements.</blockquote>



<table summary="Spatial structure">
 
<tr>
  <td valign="top"><img src="../../../figures/ifcbuildingstorey-spatialstructure.png" alt=
"IfcBuildingStorey as part of a spatial structure" width="800" height="420" border="0"></td>
 </tr>
 
<tr>
  <td><p class="figure">Figure 3 &mdash; Building storey composition</p></td>
 </tr>

</table>

<p>Figure 4 describes the heights and elevations of the <em>IfcBuildingStorey</em>.
<ul>
 <li>elevation of storey provided by: <em>IfcBuildingStorey.Elevation</em> as a local height value relative to <em>IfcBuilding.ElevationOfRefHeight</em>, it is usually the top of construction slab</li>
 <li>net height of storey, also referred to as total height or system height (top of construction slab to top of construction slab above): provided by BaseQuantity with Name="GrossHeight"</li>
 <li>net height of storey (top of construction slab to bottom of construction slab above): provided by BaseQuantity with Name="NetHeight"</li>
</ul>

<table summary="attributes" cellpadding="2" cellspacing="2">
 <tr>
  <td align="left" valign="top"><img src="../../../figures/ifcbuildingstorey_heights.png" alt="space heights" border="0" height="400" width="450"></td>
  <td align="left" valign="top"></td></tr>
<tr><td><p class="figure">Figure 4 &mdash; Building storey elevations</p></td></tr>
</table>

<blockquote class="history">
HISTORY&nbsp; New entity in IFC1.0</blockquote>
